Entopeltacites remberi sp. nov. from the Miocene of Clarkia, Idaho, USA

The Vizellaceae is one of the few families of fungi that can be identified solely on the basis of vegetative features, which makes the fossil members of the family readily identifiable. The family, with records to the Eocene of the northern and southern hemispheres, is a small group containing approximately twenty extant and seven fossil species. A new representative of the genus Entopeltacites within the Vizellaceae is described from the Miocene Clarkia locality of Idaho, USA. These fungi are present only on leaves of Persea. Hyphae extend across the entire leaf surfaces in straight lines, branching at 30 to 60° angles, rarely close to 90, with overlap between adjacent colonies. The hyphae are 4 to 5 μm in diameter, and regularly alternate between dark segments that are 8 to 11 μm long and hyaline segments that are 20 to 26 μm long. Single-celled hyphopodia are present but infrequent. Reproductive structures are 30 to 80 μm in diameter and are ostiolate, but internal structures are not preserved. No spores are present. This fungus differs from the other known species of Entopeltacites in its combination of hyphal and reproductive features, particularly in the regularity of cell type alternation.